The known spermicidal agents, nonoxynol-9 (N9) and gramicidin, exert their effects via a detergent-like ability to damage the sperm plasma membrane, perturb its conformation and destroy its semi-permeable nature thereby impairing the sperm motility and egg fertilizing functions (Wilborn, et al., Fertil Steril 1983; 39:717-719; Bourinbaiar, et al., Life Sci 1994; 54:PL 5-9). Because of their non-specific membrane disruptive properties, such vaginal spermicides have been shown to damage the cervicovaginal epithelium, as well, which may lead to a lower degree of protection from sexually transmitted diseases (Niruthisard, et al., Sex Transm Dis 1991; 18:176-179). A vaginal contraceptive that does not function with the non-specific membrane toxicity mediated by detergent-type action of the currently available vaginal contraceptives would be desirable.
In addition, the dangers of sexually-transmitted diseases have been widely recognized. However, despite the educational and preventive measures taken to date, the spread of diseases such as HIV remains a serious health problem. It would be desirable to provide a contraceptive that also provides some protection against sexually-transmitted diseases such as HIV, especially to reduce the risks for women who otherwise would be at high risk of acquiring such diseases by heterosexual transmission.